Tread-belt link and cooperating driving tumbler



Nov. 21, 1950 T. o. DAVIDSON 2,530,379

TREAD-BELT LINK AND COOPERATING DRIVING TUMBLER Filed Oct. 30, 1947 2 Sheets-Sheet 1 36a Z I 22 .21 6

A Z l ATTORNEY Nov. 21, 1950 T. o. DAVIDSON 2,530,379

TREAD-BELT LINK AND COOPERATING DRIVING TUMBLER Filed 001:. 30, 1947 2 Sheets-Sheet 2 F? .5. m fi Mm,

INVENTOR,

BY a W ATTORNEY Patented Nov. 21, 1950 TREAD-BELT LINK AND COOPERATING DRIVING TUMBLER Trevor 0. Davidson, Milwaukee, Wis., assignor to Bucyrus-Erie Company, South Milwaukee, Wis., a corporation of Delaware Continuation of application Serial No. 739,631, April 5, 1947. This application October 30, 1947, Serial No. 783,192

15 Glairns.

.filed April '5, 1947, for improvements in Tread- Belt Links and Cooperating Tumblers, now abandoned.

It represents one further step in the improvement of that type of links and tumblers, successive developments of which are shown and described in the patent of February 23, 1926-, No. 1,574,042, to Bager and Lehman, and in the patent of May 20, 1930, No. 1,759,049, to Mitchell L. Fykes, and in the patent of February 20, 1934,

No. 1,947,883, to Thomas A. Snyder.

The principal objects of my present invention are to redesign and improve said former links so that: (a) wear on the roller-track will not afiect driving engagement; (b) the wear incident to the rocking motion of the former link as it goes into and out of engagement with the tumblers will be largely eliminated; there will be provided a striking contact, instead of a wiping contact, between the driving lugs of the driving tumbler and the driving lugs of the links, so as to reduce wear of the cooperating surfaces of these links; (d) tendency of the rollers and/or idler tumbler to climb over instead of pass between the driving lugs of the links will be eliminated; and (e) the link will be reversible, so as to equalize the wear thereon.

In addition to the objects above stated, I have worked out a number of novel and useful details, which will be readily evident as the description progresses.

My invention consists in the novel parts, and in the combination and arrangement thereof, which are defined in the appended claims, and of which one embodiment is exemplified in the accompanying drawings, which are hereinafter particularly described and explained.

Throughout the description, the same reference number is applied to the same member or to similar members.

Referring now to the accompanyingdrawings all Figure 3 is a vertical section, taken along the line 33 of Figure 1.

Figure 4 is a vertical section, taken along the line 4-4' of Figure 1.

Figure 5 is a vertical section, line 5--5 of Figure 1.

Figure 6 is an elevation, taken along the line 6-5 of Figure 1.

Figure '7 is a plan View of a portion of my link, as seen from above, showing an alternative construction thereof.

Figure 8 is a reduced side elevation of my complete creeping traction unit.

Figure 9 is a side elevation of enough of my driving tumbler to illustrate the construction of the entire tumbler, together with one link and parts of two others in driving engagement with said tumbler.

Figure 10 isa transverse section of the tumbler taken along the and of two interconnected links, taken along the 2 I, 2| are two upstanding Wheel-guiding driving-fianges, which laterally bound a longitudinally extending single narrow wheel-receiving channel 22. cated directly opposite each other laterally across the channel, but this is not essential, although advisable. Each of these flanges contains a dirtextruding opening 23 similar tothose of the already-mentioned Fykse patent, for the same purpose as the similar openings of that patent, and as the functionally similar openings of the already-mentioned Snyder patent. It will be noted, from Figures 3 and 4, that the top surface of each flange is substantially semi-circular in a longitudinal direction; this facilitates en'- gagement with and disengagement from the driving tumbler to be hereinafter described.

On each laterally extending edge of the link, there are a series of ears24 to 28, defining a series of openings 29 to 33-. Many of these ears contain transverse holes, such as 34, for the insertion of pivot-pins 35 (shown in Figures 9 and- 10) for the purpose of hinging successive links together.

Longitudinally aligned with each flange 2|,

These flanges are shown 10-- there is a tumbler-bearing surface 36, located on ear 26 and above the level of the floor of channel 22. From the symmetry of the link through a vertical axis located at point A in Figure 1, it will be readily evident that each of surfaces 36 will have opposite it across the channel 22 a surface 35 of the adjoining link, such surface being on ear 26 of the adjoining link, which car fits into recess 3| of the link first mentioned.

Channel 22 is flared in width toward the edge of the link by making inner edge 36a of surface 38 oblique with reference to the axis of the channel. This flare guides the lower rollers and/ or idler tumbler (hereinafter described) into the channel, thereby eliminating any tendency for them to climb over surface 35 and flanges 2| instead of passing along channel 22 between the flanges. The flare may be obtained by making the oblique inner edge of surface 36 either bevelled, as shown at 36a in Figure 1, or vertical, as shown at 36a in Figure 7, or by using any other equivalent surface having the desired guiding effect.

There are also on each link two roller-bearing surfaces 31 for contact with the upper rollers 38 (see Figure 8).

The remaining structural features of my link are merely for convenience in casting, and hence need not be described in detail.

Turning now to Figures 9 to 11, and especially to Figure 9, we see that 39 is my driving tumbler. This tumbler has on each face a succession of peripheral recesses 40, for reception of and driving contact with the paired driving-flanges 2| of the links. Between successive recesses so there is a bearing-surface 4|, extending laterally across the periphery of the tumbler, and resting on tumbler-bearing surfaces 38 of the links. It is to be noted that the portions 42 of the periphery of the tumbler, intermediate the bearingsurfaces 4| of the tumbler, are clear of and do not rest upon the channel 22 of the links.

It will be noted that the tumbler-bearing surfaces Si of the link are so inclined in a longitudinal direction as to be perpendicular to the radius of the tumbler, when the link is in engagement with the tumbler.

Turning finally to Figure 8, we see the assembly of my complete creeping traction unit. 46 is the frame. 38 are the upper-rollers. 39 is the driving tumbler. 43 are the lower-rollers which serve to support the frame. 44 is another tumbler, not necessarily but preferably an idler tumbler, as here shown.

As already explained, the two tumblers 39 and 44 and the lower rollers 43 run in the channel 22 between the upstanding flanges 2| on the links of the chain 15. The bearing-surfaces lla on the tumbler 39, extend out laterally beyond the confines of the channel 22 between'the flanges 2| of successive links, and serve to drive the chain. The paired upper rollers 38 run on their own two outside paths 3i, and support the upper reach of the chain.

From the foregoing description, it will be evident that, inasmuch as the driving tumbler 39 does not run on the roller-track formed by the channels 22 of successive links, wear on this track will not effect driving engagement of the laterally-extending driving surfaces lla (Figure 9) of the driving tumbler 35? with the upstanding flanges 2| on the links; that, inasmuch as the driving tumbler 39 bears upon the chain at the joints between successive links, and that the bearing-surfaces 35 on the links at those points are perpendicular to the radii of the driving tumbler, there will be little, if any, rocking motion of the links as they go into and out of engagement with the driving tumbler; that, due to the slopes of the upstanding flange 2| on each link and of the corresponding surface 4 la on the driving tumbler, the pressure line between these surfaces at their point of contact passes between the pin centers of the link so that the driving tumbler will have a striking contact rather than a wiping contact with the upstanding flange '2! on the link; and that the links are reversible. All of this increases precision, and reduces and equalizes wear, and reduces the effect of such slight wear as there may be.

To simplify the understandability of the claims, the ground-engaging portion of the link will be called the bottom face, the opposite surface will be called the top, the direction of travel of the chain will be called longitudinal, the direction perpendicular thereto (i. e., across the chain from side to side) will be called lateral, and the edges of the link which adjoin succeeding and preceding links will be called the laterally extending edges.

Having now described and illustrated one form of my invention, I wish it to be understood that my invention is not to be limited to the specific form or arrangement of parts herein described and shown.

I claim:

1. A tread belt link for a creeping traction unit, said link having: a ground-engaging sure face on the bottom face thereof; a wheel-receiving channel on the top face thereof; two upstanding wheel-guiding driving flanges, located opposite each other laterally across the channel; at least one tumbler-bearing surface laterally disposed with respect to the channel, and longitudinally aligned with a driving-flange; and means for connection to adjoining links.

2. A tread belt link for a creeping traction unit, said link having: a ground-engaging surface on the bottom face thereof; a wheel-receiving channel on the top face thereof; at least one upstanding wheel-guiding driving-flange laterally disposed with respect to said channel; at least one tumbler-bearing surface laterally disposed with respect to said channel; and means for connection with adjoining links; further characterized by the fact that the channel is flared outwardly in width toward one end, adjacent the tumbler-bearing surface, and that this flared portion is defined by an oblique beveled edge of said surface.

3. A tread belt link for a creeping traction unit, said link having: a ground-engaging surface on the bottom face thereof; a wheel-receiving channel on the top face thereof; at least one upstanding wheel-guiding driving-flange laterally disposed with respect to said channel; at least one tumbler-bearing surface laterally disposed with respect to said channel; and means for connection with adjoining links; further characterized by the fact that each tumbler-bearing surface extends above the level of the floor of the channel.

4. A tread belt link according to claim 3, further characterized by the fact that each tumbler-bearing surface has such a longitudinal slope that, when the link is in engagement with the driving-tumbler with which it is designed to cooperate, this slope will be perpendicular to the radius of the tumbler.

5. A tread belt link according to claim 4, further characterized by the fact that the drivingflanges are two in number, and are located opposite each other laterally across the channel, and that each tumbler-bearing surface is longitudinally aligned with a driving-flange.

6. A tread belt link according to claim 5, further characterized by the fact that the tumblerbearing surfaces are two in number, one being longitudinally aligned with each driving-flange,

7. A tread belt link for a creeping traction unit, said link having: a ground-engaging surface on the bottom face thereof; a Wheel-receiving channel on the topface thereof; at least one upstanding wheel-guiding driving-flange laterally disposed with respect to said channel; at least one tumbler-bearing surface laterally disposed with respect to said channel; and means for connection with adjoining links; further characterized by the fact that the connecting means are a series of cars and recesses along the laterally extending edges of the links, and that each tumbler-bearing surface is on an ear, and that a recess is located just across the channel from each such ear.

8. A tread belt link according to claim 7, further characterized by the fact that each tumbler-bearing surface extends above the level of the floor of the channel.

9. A tread belt for a creeping traction unit, said belt comprising a series of connected links, each link having: a ground-engaging surface on the bottom face thereof; a wheel-receiving channel on the top face thereof; two upstanding wheel-guiding driving flanges, located opposite each other laterally across the channel; at least one tumbler-bearing surface laterally disposed with respect to the channel, and longitudinally aligned with a driving-flange; and means for connection to adjoining links.

10. A tread belt according to claim 9, further characterized by the fact that the connecting means are a series of cars and recesses along the laterally extending edges of the link; that each such tumbler-bearing surface is on an ear, and extends above the level of the floor of the channel, with such a longitudinal slope that, when the link is in engagement with the driving-tumbler with which it is designed to cooperate, this slope will be perpendicular to the radius of the tumbler; and that a pivot-recess is located just across the channel from each such ear.

11. In a creeping traction unit, comprising a frame, at least one supporting roller, and a tumbler, all journaled in the frame, and all aligned in a single longitudinal row, the combination of a tread belt, consisting of links, each link having a ground-engaging surface, a wheel-receiving channel for the tumblers and roller, at least one upstanding wheel-guiding driving-flange laterally disposed with respect to the channel, means for connecting adjoining links, and at least one tumbler-bearing surface laterally disposed with reing peripheral recesses for reception of and driv ing contact with the driving-flanges of the links, and laterally extending peripheral bearing-sunfaces to bear on the tumbler-bearing surfaces of the links.

12. The combination according to claim 11, further characterized by the fact that the driving-flanges are two in number, one being on each side of the channel; that the tumbler-bearing surfaces of each link are two in number, one being aligned With each driving-flang of that link; that the connecting means are a series of ears and recesses along the laterally extending edges of the link; that each such tumbler-bearing surface is on an ear; and that a recess of the same link is located just across the channel from each such ear.

13. The combination according to claim 12, further characterized by the fact that each such tumbler-bearing surface extends above the level of the floor of the channel; and that each peripheral bearing-surface of the tumbler extends laterally across the periphery of the tumbler to bear on one tumbler-bearing Surface of a link 15. A driving tumbler for a creeping traction unit, said tumbler having paired peripheral recesses for reception of and driving contact with upstanding paired driving-flanges on cooperating links; and having, between successive recesses, a load supporting surface extending laterally across the periphery, perpendicular to the radius of the tumbler.

TREVOR O. DAVIDSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 257,445 Lechner May 2, 1882 296,192 Legg Apr. 1, 1884 1,419,390 Krupp June 13, 1922 1,446,292 George Feb. 20, 1923 1,569,099 Miller Jan. 12, 1926 1,574,042 Bager et a1 Feb. 23, 1926 1,759,049 Fykse May 20, 1930 1,835,627 Bauer Dec. 8, 1931 1,947,883 Snyder Feb. 20, 1934 2,452,921 Gillespie Nov. 2, 1948 FOREIGN PATENTS Number Country Date 218,184 Great Britain July 3, 1924 

